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Gave up!

Hi!

I gave it all up since most of the tutorials were made for Softimage and the support where to technical to me!

I do not understand why its still a fact that many developers that are skilled in technical solutions and their own programs does or dont's still do not get the fact that the software is not made for their joy and purpose.

I guess programs compared to Syflex would have been a greater success if the information where more basic, with rookies and less technical advanced users in focus and the video tutorials were more pedagogic. Syflex would also have benefited from a large library of presets with skull shaped items that could easily be replaced with similar objects. This could as well be valid for body shapes, four legged creatures and whatever... if this sounds like a heavy job for the Syflex authors just imagine how it feels like a newcomer when every little change in one setting affects a bunch of others. Totally insane circus of possible errors

Looks nice as most things from that app, but notice the calculation times. Good cloth takes time to calculate even in Houdini. Could take quite some time to tweak the settings an get things right when it takes several minutes a frame. I would suggest sculpt some morphs or displacements to add wrinkels so it looks like cloth.

Looks nice as most things from that app, but notice the calculation times. Good cloth takes time to calculate even in Houdini. Could take quite some time to tweak the settings an get things right when it takes several minutes a frame. I would suggest sculpt some morphs or displacements to add wrinkels so it looks like cloth.

From what I recall, you can import an animation from Lightwave to Marvelous Designer, run your sim, and then export an MDD for LightWave. Pretty standard for the most part.

The 'non-standard' part was that you need to create the fabric items within MD for the dynamics to work, and MD expects clothing to be cut and stitched exactly like the real thing, so no modeling cheats allowed. This part didn't work for the productions I've been involved with because fabric items were typically modeled in LightWave, ZBrush or Maya.

I don't think the MD workflow has changed but it's been a while since I last used the program.

I've generally had good luck with Bullet. I need to use real geometry, not sub-d's, to get good details in the folds. Sometimes you need to build features into the rig to help it along.

I was trying to use Bullet to do some cloth like deformations, I couldn't wrap my head around.
Greenlaw ..can you post your work?

Sure. I threw this demo scene together this evening. Sorry for the craptacular geometry--I didn't want to spend too much time on this--but I think this demo may give you ideas for what's possible if more time was spent to make it nice. Plus, it's been a while since I last worked with Bullet for a cloth sim so this was a good refresher for me.

The first part of the demo shows the simulation calculating in realtime. I think it took about a minute on my pokey old workstation, which is pretty fast, I think. Certainly much faster than ClothFX, which is why I hardly ever use that tool any more. After the sim is calculated it plays back in actual speed three times, and then finally we see a quick and dirty render of the animation.

Here's what the geometry looks like.

It's pretty simple but the key here was to make the polygons more or less the same size. I also split some polygons to help the mesh crease where it should 'hang'. With a better shirt mesh and collision objects, the fabric should hang more realistically.

I should clarify something I said earlier about Bullet and sub-d surfaces. You can use sub-d surfaces with Bullet but be aware that Bullet always uses the geometry in its 'pre-sub-divided' form. This means, your base geometry will to have enough actual geometry to allow the folding effect happen. Any sub-d that occurs after that will make what's already there looks smoother. If you're geometry is too simple, or has wildly irregular polygons distribution, don't expect Bullet to perform miracles with it.

Remember what I said about Marvelous Designer and why it requires you to model the clothing using its native tools? MD is a true clothing simulator and it expects fabric to 'cut and sewn' in a specific way so it can predictably animate it. Well, the same kinda holds true for Bullet--the polygons in the mesh should be more or less the same size and evenly distributed as in the above example, and it doesn't hurt to make the polygons flow a certain way to influence how the fabric hangs and folds. Take time to experiment with simple shapes like draping squares and cylinders to see how Bullet animates them, then apply what you learn on more complex shapes like shirts, pants, and capes.

As for Bullet settings, I mostly used default settings for this demo. I admit it could look better with some tweaking but I wanted to show there are no special magical settings for this. It's mostly about using appropriate geometry.

I think the main thing I did was to reduce friction for both collision and shirt objects, and I slightly increased the Collision Margin for the shirt. Oh, and I increased the Dampening Coefficient to keep the shirt from flapping too much. Finally, I doubled the Dynamics Framerate to 380. It's actually not horrible at the default of 180, but increasing it improves the collision accuracy and reduces penetration.

If you look at the mesh object, you'll see I painted weights for the cuff. This was going to be used to 'stiffen' the cuff shapes during the sim but I never got around to setting that up. I had to stop because I'd already spend way more time on this than I should have. But I hope mentioning this trick will give you some ideas for your own sim.

Also, note that I used a few cheats here. For example, the collision objects are basically spheres and capsules to speed up the calculations and I hid them so you didn't see any penetration. On a real job, I may only have a day or so to get a shot done (sometimes less,) so I usually go for the fastest/cheapest way to get good results. If this were for a real production scene, I might remove parts of the actual character mesh from under the fabric if I thought that would speed up a render, or to avoid mesh penetration. Better safe than sorry, especially on a deadline where you may get only one chance to get a render right.

There are other things you can do to improve this, like animating collision objects beneath the surface to 'sculpt' the fabric the way you want. You can also build in creases and deforming effects on top of the actual simulation to make it look even more like what you'd expect. (Or MDD it and use Chronosculpt to enhance it!)

Bullet is actually pretty easy to use and reasonably predictable once you understand the rules. Anytime I'm faced with a new challenge, I find it helps a lot to study what Bullet does with very basic shapes, and then build from there to make it do what I need for more complicated setups. And don't be afraid to cheat...you can trick Bullet into doing almost anything by animating 'invisible hands' to guide it.

Hope this helps. I think if you search these forums, you may find other examples that other artists and I have posted over the years.

Self Collision may solve issues like the penetration that's occuring in the elbows, but in my experience, it will probably create new problems. In this case, it made the shirt jitter and I just didn't want to deal with that.

I generally avoid Self Collision as much as possible because it may take too much time to solve any problems it might cause, plus it can dramatically increase the calculation times.

Most of the time I've been able to set things up so that the lack of Self-Collision isn't really noticeable.

If this were an actual production scene, I would add more detail the these objects, but probably not a whole lot more.

It's possible to use the actual character mesh for collision in Bullet, but you'll need to scan it to MDD and make it a Deformable Bullet Object. Personally, I don't recommend this unless you have many hours to spend waiting on the sim to complete.

I find using simple meshes and Kinematic mode can be as effective and probably more predictable to work with. Plus I'd rather wait a few minutes than sit around all day to get my computer back. (I like to pretend I have a life.)